Channel quality reporting for adaptive sectorization

ABSTRACT

Apparatuses and methodologies are described that enhance performance in a wireless communication system using beamforming transmissions. According to one aspect, the channel quality is monitored. Channel quality indicators can be used to select a scheduling technique, such as space division multiplexing (SDM), multiple-input multiple output (MIMO) transmission and opportunistic beamforming for one or more user devices. In addition, the CQI can be used to determine the appropriate beam assignment or to update the beam pattern.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent claims priority to ProvisionalApplication Nos. 60/672,575 entitled “CHANNEL QUALITY REPORTING FORADAPTIVE SECTORIZATION IN WIRELESS COMMUNICATION SYSTEMS” filed Apr. 19,2005, and 60/710,419 filed Aug. 22, 2005 which are assigned to theassignee hereof and hereby expressly incorporated by reference herein.

REFERENCE TO CO-PENDING APPLICATIONS FOR PATENT

The present Application for Patent is related to the followingco-pending U.S. Patent Applications: “ADAPTIVE SECTORIZATION IN CELLULARSYSTEMS” having Attorney Docket No. 050917, filed concurrently herewith,assigned to the assignee hereof, and expressly incorporated by referenceherein; and

“Beam-Space Precoding For Sdma Wireless Communication Systems” havingAttorney Docket No. 051217, filed concurrently herewith, assigned to theassignee hereof, and expressly incorporated by reference herein. “SDMAResource Management” having Attorney Docket No. 060031, filedconcurrently herewith, assigned to the assignee hereof, and expresslyincorporated by reference herein; and

“Mobile Wireless Access System” having Attorney Docket No. 060081, filedconcurrently herewith, assigned to the assignee hereof, and expresslyincorporated by reference herein.

BACKGROUND

I. Field

The following description relates generally to wireless communications,and, amongst other things, to communication schemes for wirelesscommunication systems.

II. Background

Wireless networking systems have become a prevalent means by which amajority of people worldwide has come to communicate. Wirelesscommunication devices have become smaller and more powerful in order tomeet consumer needs and to improve portability and convenience.Consumers have found many uses for wireless communication devices suchas cellular telephones, personal digital assistants (PDAs) and the like,demanding reliable service and expanded areas of coverage.

A typical wireless communication network (e.g., employing frequency,time, and code division techniques) includes one or more base stationsthat provide a coverage area and one or more mobile (e.g., wireless)user devices that can transmit and receive data within the coveragearea. A typical base station can simultaneously transmit multiple datastreams for broadcast, multicast, and/or unicast services, wherein adata stream is a stream of data that can be of independent receptioninterest to a user device. A user device within the coverage area ofthat base station can be interested in receiving one, more than one orall the data streams carried by the composite stream. Likewise, a userdevice can transmit data to the base station or another user device.Such communication between base station and user device or between userdevices can be degraded due to channel variations and/or interferencepower variations. For example, the aforementioned variations can affectbase station scheduling, power control and/or rate prediction for one ormore user devices.

Performance for a wireless communication system may be enhanced by usingbeamformed transmissions to communicate from the base station to themobile devices. Multiple transmit antennas located at a base station canbe used to form beamformed transmissions. Beamformed transmissions, alsoreferred to as beams, typically cover a narrower area than transmissionsusing a single transmit antenna. A beam can be considered a virtualsector allowing a virtual six-sector system to be generated from aconventional three-sector system. However, the signal to interferenceand noise ratio (SINR) is enhanced within the area covered by the beams.The communication system can utilize a fixed or predetermined set ofbeams. Although the fixed beam pattern can be updated or adapted, incontrast to a beam steering system, the beams in a fixed beam system arenot dynamically updated based on individual user devices.

Typically, user devices should be assigned to appropriate beams tooptimize channel performance. In addition, the beamforming system canutilize a variety of scheduling techniques based upon spatial, frequencyor time divisions. The system should select the technique or combinationof techniques to optimize channel performance, and consequently systemperformance. Thus, there exists a need in the art for a system and/ormethodology for monitoring channel quality to optimize selection ofbeams and transmission techniques.

SUMMARY

The following presents a simplified summary of one or more embodimentsin order to provide a basic understanding of such embodiments. Thissummary is not an extensive overview of all contemplated embodiments,and is intended to neither identify key or critical elements of allembodiments nor delineate the scope of any or all embodiments. Its solepurpose is to present some concepts of one or more embodiments in asimplified form as a prelude to the more detailed description that ispresented later.

In accordance with one or more embodiments and corresponding disclosurethereof, various aspects are described in connection with enhancingperformance in a wireless communication system using beamformingtransmissions. According to one aspect, the channel quality ismonitored. Channel quality indicators can be used to select a schedulingtechnique, such as space division multiplexing (SDM), multiple-inputmultiple output (MIMO) transmission and opportunistic beamforming forone or more user devices. In addition, the CQI can be used to determinethe appropriate beam assignment or to update the beam pattern.

To that end, a method for enhancing performance for a wirelesscommunication environment is described herein. The method can includegenerating a first pilot, transmitting the first pilot and receiving atleast one channel quality indicator (CQI) based at least in part uponthe first pilot. The method can also comprise scheduling at least oneuser device based at least in part upon the at least one CQI.Additionally, the method can comprise assigning a user device to a beambased upon the at least one CQI. The method can also comprise generatinga second pilot, transmitting the second pilot on a second beam andreceiving a second CQI based at least in part upon the second pilot.Moreover, the method can comprise receiving a pilot, determining a CQIbased at least in part upon the pilot and transmitting the CQI to a basestation.

According to yet another aspect, an apparatus for wireless communicationcan comprise a processor configured to generate a first pilot, transmitthe first pilot and receive at least one CQI based at least in part uponthe first pilot and a memory coupled with the processor. The processorcan also be configured to schedule at least one user device based atleast in part upon the at least one CQI. Additionally, an apparatus cancomprise a processor configured to receive a pilot, determine at leastone CQI based at least in part upon the pilot and transmit the CQI to abase station.

According to another aspect, an apparatus for enhancing performance fora wireless communication environment can comprise a means for generatinga first pilot, a means for transmitting the first pilot and a means forreceiving at least one channel quality indicator (CQI) based at least inpart upon the first pilot. The apparatus can also comprise a means forgenerating a second pilot, a means for transmitting the second pilot ona second beam and means for receiving a second CQI based at least inpart upon the second pilot.

Yet another aspect relates to a computer-readable medium having storedthereon computer-executable instructions for generating a first pilot,transmitting the first pilot, receiving at least one channel qualityindicator (CQI) based at least in part upon the first pilot andscheduling at least one user device based at least in part upon the atleast one CQI. In addition, the instructions can comprise generating asecond pilot, transmitting the second pilot on a second beam andreceiving a second CQI based at least in part upon the second pilot.

Yet another aspect relates to a processor that executes instructions forenhancing performance for a wireless communication environment, theinstructions can comprise generating a first pilot, transmitting thefirst pilot, receiving at least one channel quality indicator (CQI)based at least in part upon the first pilot and scheduling at least oneuser device based at least in part upon the at least one CQI.Additionally, the instructions can comprise generating a second pilot,transmitting the second pilot on a second beam and receiving a secondCQI based at least in part upon the second pilot.

A further aspect sets forth a mobile device that can comprise acomponent that generates a first pilot, a component that transmits thefirst pilot and a component that receives at least one channel qualityindicator (CQI) based at least in part upon the first pilot. Moreover,the mobile device is at least one of a cellular phone, a smartphone, ahandheld communication device, a handheld computing device, a satelliteradio, a global positioning system, a laptop, and a PDA.

To the accomplishment of the foregoing and related ends, the one or moreembodiments comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe one or more embodiments. These aspects are indicative, however, ofbut a few of the various ways in which the principles of variousembodiments may be employed and the described embodiments are intendedto include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS.

FIG. 1 is an illustration of a wireless communication system accordingto one or more aspects presented herein.

FIG. 2 is an illustration of a wireless communication system accordingto one or more aspects presented herein.

FIG. 3 illustrates a beam pattern for a wireless communication system inaccordance with various aspects presented herein.

FIG. 4 illustrates a methodology for monitoring channel quality inaccordance with one or more aspects presented herein.

FIG. 5 illustrates a methodology using a dedicated pilot to monitorchannel quality in accordance with one or more aspects presented herein.

FIG. 6 illustrates a methodology for monitoring channel quality using along term CQI in accordance with one or more aspects presented herein.

FIG. 7 is an illustration of a system that monitors channel quality toimprove performance in a wireless communication environment inaccordance with various aspects presented herein.

FIG. 8 is an illustration of a system that monitors channel quality toimprove performance in a wireless communication environment inaccordance with various aspects presented herein.

FIG. 9 is an illustration of a wireless communication environment thatcan be employed in conjunction with the various systems and methodsdescribed herein.

DETAILED DESCRIPTION

Various embodiments are now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of one or more embodiments. It may be evident, however,that such embodiment(s) may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing one or more embodiments.

Furthermore, various embodiments are described herein in connection witha user device. A user device can also be called a system, a subscriberunit, subscriber station, mobile station, mobile device, remote station,access point, base station, remote terminal, access terminal, userterminal, terminal, user agent, or user equipment (UE). A user devicecan be a cellular telephone, a cordless telephone, a Session InitiationProtocol (SIP) phone, a wireless local loop (WLL) station, a PDA, ahandheld communications or computing device having wireless connectioncapability, a smartphone, a satellite radio, a global position system, alaptop, or other processing device connected to a wireless modem.

Moreover, various aspects or features described herein may beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. The term “article ofmanufacture” as used herein is intended to encompass a computer programaccessible from any computer-readable device, carrier, or media. Forexample, computer readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips. . . ), optical disks (e.g., compact disk (CD), digital versatile disk(DVD) . . . ), smart cards, and flash memory devices (e.g., card, stick,key drive . . . ).

While the disclosure discusses beamforming as a mode of operation, thedisclosure and its contents may substantially be applied to precoded orbeam-steered transmissions. This may be performed by, for example,utilizing fixed or predetermined matrices or vectors for which a user isscheduled.

Referring now to FIG. 1, a wireless communication system 100 inaccordance with various embodiments presented herein is illustrated.System 100 can comprise one or more base stations 102 in one or moresectors that receive, transmit, repeat, etc., wireless communicationsignals to each other and/or to one or more mobile devices 104. Eachbase station 102 can comprise multiple transmitter chains and receiverchains, e.g. one for each transmit and receive antenna, each of whichcan in turn comprise a plurality of components associated with signaltransmission and reception (e.g., processors, modulators, multiplexers,demodulators, demultiplexers, antennas, etc.). Mobile devices 104 canbe, for example, cellular phones, smart phones, laptops, handheldcommunication devices, handheld computing devices, satellite radios,global positioning systems, PDAs, and/or any other suitable device forcommunicating over wireless system 100. In addition, each mobile device104 can comprise one or more transmitter chains and a receiver chains,such as used for a multiple input multiple output (MIMO) system. Eachtransmitter and receiver chain can comprise a plurality of componentsassociated with signal transmission and reception (e.g., processors,modulators, multiplexers, demodulators, demultiplexers, antennas, etc.),as will be appreciated by one skilled in the art.

Referring now to FIG. 2, a multiple access wireless communication system200 according to one or more embodiments is illustrated. A 3-sector basestation 202 includes multiple antenna groups, one including antennas 204and 206, another including antennas 208 and 210, and a third includingantennas 212 and 214. According to the figure, only two antennas areshown for each antenna group, however, more or fewer antennas may beutilized for each antenna group. Typically, beamforming techniquesrequire multiple transmit antennas to transmit beams. Mobile device 216is in communication with antennas 212 and 214, where antennas 212 and214 transmit information to mobile device 216 over forward link 220 andreceive information from mobile device 216 over reverse link 218.Forward link (or downlink) refers to the communication link from thebase stations to mobile devices, and the reverse link (or uplink) refersto the communication link from mobile devices to the base stations.Mobile device 222 is in communication with antennas 204 and 206, whereantennas 204 and 206 transmit information to mobile device 222 overforward link 226 and receive information from mobile device 222 overreverse link 224.

Each group of antennas and/or the area in which they are designated tocommunicate may be referred to as a sector of base station 202. In oneor more embodiments, antenna groups each are designed to communicate tomobile devices in a sector or the areas covered by base station 202. Abase station may be a fixed station used for communicating with theterminals and may also be referred to as an access point, a Node B, orsome other terminology.

A wireless communication system can include one or more base stations incontact with one or more user devices. Each base station providescoverage for a plurality of sectors. In communication with a userdevice, the transmitting antennas of a base station can utilizebeam-forming techniques in order to improve the signal-to-noise ratio offorward links for the different mobile devices. Additionally, a basestation using beamforming to transmit to mobile devices scatteredrandomly through its coverage area can cause less interference to mobiledevices in neighboring cells/sectors than a base station transmittingthrough a single antenna to all mobile devices in its coverage area.Generally, beams generated by multiple transmit antennas are narrowerthan the coverage area of a single antenna. While user devices in theareas covered by beams experience an enhanced SINR, user devices withinthe null region experience a low SINR, possibly leading to loss of data.In general, user devices in the null region are worse off than if asingle transmit antenna had been utilized to transmit data. In addition,if a user device located within a beam selects the wrong beam forcommunications, the user device will experience the same decrease inperformance as user devices located in the null region.

FIG. 3 illustrates a beam pattern 300 for use in a wirelesscommunication system in accordance with one or more embodimentspresented herein. Base station transmit antennas can generate beamscovering predetermined areas, resulting in a fixed beam pattern. Thebeam pattern can be adjusted periodically or adjustment of the patterncan be event driven. For example, the beam pattern can be modified basedupon patterns of communication between the user devices and the basestation. In the beam pattern illustrated in FIG. 3, multiple antennas ata base station 302 emit a first fixed beam 304 and a second fixed beam306 for a sector 308. The number of beams shown has been limited to twofor the sake of simplicity; however, multiple, additional fixed beamsmay be generated. Beams may be generally orthogonal as shown in FIG. 3or the coverage area of the beams may overlap. Users U1 and U2 arelocated within the coverage area of beams 306 and 304, respectively.Consequently, Users U1 and U2 experience an enhanced SINR, similar tothe benefits experienced by users in a beam-steering system. Incontrast, Users U3 and U4 will experience an extremely low SNR sincethey are located within the null region of the beams 306 and 304. Infact, the performance for users U3 and U4 may be worse than if a singletransmit antenna had been utilized. In addition, user devices mayexperience reduced SINR if the user device selects the wrong beam. Forexample, user device U1 is located within the coverage are of secondbeam 306. However, if user device U1 were to incorrectly electtransmissions over first beam 304 or if the user device U1 is assignedto first beam 304 by the base station, the user device will experiencethe same performance as if the user device was located in the nullregion.

Beamforming techniques can be used to provide fixed transmit directionsin sectors or may be used in lieu of sectors. For example, beam patternsmay provide multiple transmit directions in the sectors of a 3-sectorbase station, resulting in a virtual 6-sector base station. This abilityto subdivide sectors when combined with various scheduling techniquesresults in increased system capacity.

Beamformed transmissions may be used with a number of differentscheduling schemes, including space division multiplexing (SDM). SDM isa technique used in a multiple antenna communication system thatutilizes the spatial dimensions to support additional user devices fordata transmissions. In a space division multiple access system (SDMA)system, the base station can use the same frequencies to transmit tomultiple user devices at the same time where the user devices areassigned to separate beams.

The multiple input multiple output (MIMO) and opportunistic beamformingscheduling techniques can be used with fixed beamforming patterns. Inparticular, user devices with well-conditioned matrix channels can bescheduled using MIMO. In a MIMO system, multiple data streamscorresponding to a single user device are scheduled at the same time andfrequency on multiple beams, thereby increasing the data rate. Incontrast, in opportunistic beamforming, also referred to as beamselection, the base station transmits to a single user device over agiven set of frequencies and time using a single beam. No other beamsare used for transmission to any other user over those frequencies andat those times.

SDM, MIMO and opportunistic beamforming can be used with frequencydivision systems such as an orthogonal frequency division multipleaccess (OFDMA) system. An OFDMA system partitions the overall systembandwidth into multiple orthogonal subbands. These subbands are alsoreferred to as tones, carriers, subcarriers, bins, and/or frequencychannels. Each subband is associated with a subcarrier that can bemodulated with data. An OFDMA system may use time and/or frequencydivision multiplexing to achieve orthogonality among multiple datatransmissions for multiple user devices. Groups of user devices can beallocated separate subbands, and the data transmission for each userdevice may be sent on the subband(s) allocated to this user device.SDMA, MIMO and opportunistic beamforming can be implemented for userdevice allocated to different frequency regions.

In a beamformed transmission system, beamforming techniques can beutilized to provide fixed transmit directions in sectors or may be usedin lieu of sectors. For example, beam patterns may provide multipletransmit directions in the sectors of a 3-sector base station, resultingin a virtual 6-sector base station. This ability to subdivide sectorsresults in increased system capacity. User devices served by a basestation sector can indicate a preference for a given beam. The basestation may schedule transmission with the user device on the given beamusing SDM, MIMO, opportunistic beamforming or any other schedulingmethod. In addition, beamforming with a fixed beam pattern allows a basestation to utilize SDM, MIMO and opportunistic beamforming schedulingtechniques simultaneously. For example, spatially orthogonal userdevices may be scheduled using SDM, user devices with well-conditionedmatrix channels could be scheduled using MIMO and additional users couldbe scheduled using opportunistic beamforming. It should be noted that inthe case of precoding or beam steering, the directions shown may be onedirection or the dominant direction of the beam.

Referring to FIGS. 4-7, methodologies relating to increasing performanceand capacity in wireless communication systems are illustrated. Forexample, methodologies can relate to using beamforming and channelquality monitoring in an SDMA environment, in an FDMA environment, anOFDMA environment, a CDMA environment, a WCDMA environment, a TDMAenvironment or any other suitable wireless environment. While, forpurposes of simplicity of explanation, the methodologies are shown anddescribed as a series of acts, it is to be understood and appreciatedthat the methodologies are not limited by the order of acts, as someacts may, in accordance with one or more embodiments, occur in differentorders and/or concurrently with other acts from that shown and describedherein. For example, those skilled in the art will understand andappreciate that a methodology could alternatively be represented as aseries of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts may be utilized to implement amethodology in accordance with one or more embodiments.

Referring now to FIG. 4, a methodology 400 for monitoring channelquality in accordance with one or more aspects is illustrated. At 402, apilot can be transmitted to the user devices. A pilot, as used herein isa signal, generally transmitted over a communication system and can beused for control, synchronization or reference purposes. A channelquality indicator (CQI) can be determined or estimated based upon thereceived pilot at 404. Typically, a CQI can be a quantity such as theSINR for the channel or the supportable rate over the channel. After theCQI is determined, it can be communicated to the base station at 406. At408, the CQI can be used to determine scheduling technique and/or thebeam assignment for one or more user devices. Using CQI in schedulingand assignment determination can optimize individual channel and overallsystem performance.

Referring now to FIG. 5, a methodology 500 for transmitting a dedicatedpilot in accordance with one or more aspects is illustrated. In adedicated pilot system, the base station transmits a separate pilot foreach beam in the sector. Use of dedicated beams allows the CQI for eachbeam to be determined. At 502, a pilot is generated for a particularbeam. At 504, it is determined whether there are additional beams withinthe sector. If yes, the method returns to 502 to generate a pilot forthe next beam. If no, all of the pilots can be transmitted on theirrespective beams at 506. Alternatively, all pilots can be calculated andtransmitted one at a time. In one or more aspects, the pilots can bestored in a lookup table. The pilots can be read from the lookup tableprior to transmission on the beams, as opposed to generating the pilotseach time the pilots are to be transmitted. The pilots can berecalculated and the lookup table updated periodically or recalculationand update of the table can be event driven. For example, pilots can beupdated based upon changes to the beam pattern.

Transmitting the pilot to the user devices provides the user deviceswith the data necessary to determine a CQI per beam or virtual sector.The pilots allow broadband channel measurements to be made. The pilotcan also be used to reconstruct the channel when beams are usedsimultaneously. For example, when the SDMA scheduling technique is used,the pilot allows the channel to be reconstructed and the SDMA CQI to becomputed. Using dedicated pilots can be particularly effective when thenumber of beams is less than the number of transmit antennas in thesector.

In one or more aspects, a common pilot can be used to determine CQIs. Acommon pilot is transmitted on every transmit antenna for the sector.The transmit antennas can be trained in several directions. The userdevices can reconstruct the beams based upon a set of beam weights. Useof a common pilot is particularly useful when there are more beams inthe beam pattern than available transmit antennas. For example, wherethere are three transmit antennas and eight beams in the sector, theantennas can be trained in three separate directions and the userdevices can use a set of beam weights for each of the eight beams toreconstruct the beams. The user devices can receive the common pilot andestimate the broadband channel on each transmit antenna based upon thecommon pilot. The user devices can reconstruct the channels andinterference and then calculate the CQI based upon the channel estimatesand a set of beam weights for the appropriate beam. In one or moreembodiments, beams are formed using a set of weights, that alter thephase, amplitude, or phase and amplitude of a particular transmissionsymbol or sample. These weights can be stored in a lookup table inmemory. The beam pattern can be updated by modifying the weights storedin the lookup table. The beam weights can be stored in a lookup tablefor use in CQI calculations. The beams can be fixed or the base stationcan signal a set of beam weights to the user devices using the overheadchannels. Use of the common pilot can be particularly effective when thebeams either are fixed or change very slowly, such that the beam weightsdo not need to be updated frequently. If the beam pattern is updated,the base station should signal the user device and send/signal theupdated set of beam weights. It should be understood that if the beamweights are known by the user device, they need not be transmitted tothe user device.

User devices can utilize either common or dedicated pilot to estimate abeam selection, SDMA and/or MIMO CQI for the sector that services theuser device. The beam selection, SDMA and MIMO CQIs can be compared todetermine the optimal scheduling method for a user device. In addition,the user device can estimate the CQIs for beams from other sectors. TheCQIs for beams from other sectors can be reported at a slower rate thanthe CQI for the sector that services the user device to reduce overhead.In addition, the user device can track the control channel CQI. Ingeneral, the control channel is transmitted on the beam with the largestarea of coverage. The CQI for the control channel is particularlyimportant for purposes such as power control.

In one or more aspects, the user device reports one or more CQIs to thebase station. The base station can use the CQI feedback to determine theappropriate scheduling technique for the user devices. The user devicecan report CQIs within the signal, such that the base station receivesCQIs continually. For example, the user device can report the CQI forall scheduling techniques within every frame or data packet transmittedto the base station. However, this may result in excessive overhead forthe system. Alternatively, the user devices can send the CQI for themode in which the user device is scheduled. For example, a user devicescheduled using beam selection can transmit the beam selection CQI basedupon the beam selection schedule; a user device using SDMA can transmitthe SDMA CQI based on SDMA schedule and so forth. In addition, userdevices can transmit using punctured coding. The control channel CQI canbe punctured with some combination of the non-control channel CQIs.

Referring now to FIG. 6, a methodology 600 for monitoring channelquality using a long term CQI in accordance with one or more aspects isillustrated. In one or more aspects, the system can utilize a long termCQI to select scheduling techniques and/or beam assignments for userdevices. Using a long term CQI rather than an instantaneous CQI canprevent a user device from being switched between beams or schedulingtechniques due to temporary fluctuations in the instantaneous CQI. At602, an instantaneous CQI is calculated. A long term CQI can becalculated based upon the instantaneous CQI, at 604. The long term CQIcan be calculated by averaging the instantaneous CQI with prior CQIsvalues. A table of prior CQI values and/or average of prior values canbe stored and the values or average used to calculate the long term CQI.In addition, weighted averaging can be used to calculate the long termCQI. At 606, it is determined whether the conditions have been met toreport the long term CQI to the base station. If yes, the long term CQIis transmitted at 608. If no, the next instantaneous CQI is calculatedat 602. The CQI can be reported periodically based upon a predeterminedperiod of time or based upon the number of instantaneous CQIscalculated. Alternatively, transmission of the long term CQIs can beevent driven. For example, the long term CQIs can be reported to thebase station when the beam pattern changes, when a user devicetransitions from a region covered by one beam to a region covered by asecond beam or when the CQI falls below a certain predeterminedthreshold. In addition, the user devices can report both long term andinstantaneous CQIs to the base station.

User devices can be reassigned to beams or the entire beam pattern canbe modified depending upon the CQI values. In general, user devices arecapable of relocating or being relocated during voice or datatransmission, and may move into or out of the coverage area provided bythe beam to which they area assigned. User devices should be reassignedas they move through the sector from the coverage area of one beam toanother. In addition, based upon the CQIs reported by multiple users,the base station can adjust the beam pattern to better service the groupof user devices.

It will be appreciated that, in accordance with one or more embodimentsdescribed herein, inferences can be made regarding transmission formats,frequencies, etc. As used herein, the term to “infer” or “inference”refers generally to the process of reasoning about or inferring statesof the system, environment, and/or user from a set of observations ascaptured through events and/or data. Inference can be employed toidentify a specific context or action, or can generate a probabilitydistribution over states, for example. The inference can beprobabilistic—that is, the computation of a probability distributionover states of interest based on a consideration of data and events.Inference can also refer to techniques employed for composinghigher-level events from a set of events and/or data. Such inferenceresults in the construction of new events or actions from a set ofobserved events and/or stored event data, whether or not the events arecorrelated in close temporal proximity, and whether the events and datacome from one or several event and data sources.

According to an example, one or methods presented above can includemaking inferences regarding the scheduling technique or beam assignmentfor one or more user devices. For example, it can be determined that theuser device has left the region covered by a first beam and entered aregion covered by a second beam and therefore, the user device should bereassigned to the second beam. In addition, it can be determined thatthe beam pattern is suboptimal for multiple user devices and the beampattern can be modified.

According to another example, inferences can be made relating to thescheduling techniques to employ during various times of the day, week,etc., such as peak hours and the like. It will be appreciated that theforegoing examples are illustrative in nature and are not intended tolimit the number of inferences that can be made or the manner in whichsuch inferences are made in conjunction with the various embodiments and/or methods described herein.

FIG. 7 is an illustration of a system 700 that facilitates beamformingin a wireless communication environment to increase system capacitylimits in accordance with one or more embodiments set forth herein.System 700 can reside in a base station and/or in a user device, as willbe appreciated by one skilled in the art. System 700 comprises areceiver 702 that receives a signal and from, for instance one or morereceive antennas, and performs typical actions thereon (e.g., filters,amplifies, downconverts, etc.) the received signal and digitizes theconditioned signal to obtain samples. A demodulator 704 can demodulateand provide received pilot symbols to a processor 706 for channelestimation.

Processor 706 can be a processor dedicated to analyzing informationreceived by receiver component 702 and/or generating information fortransmission by a transmitter 714. Processor 706 can be a processor thatcontrols one or more components of user device 700, and/or a processorthat analyzes information received by receiver 702, generatesinformation for transmission by a transmitter 714, and controls one ormore components of user device 700. Processor 806 can utilize any of themethodologies described herein, including those described with respectto FIGS. 4-6, to coordinate communications. In addition, user device 700can include an optimization component 708 that coordinates beamassignments and/or selects scheduling techniques. Optimization component708 may be incorporated into the processor 706. It is to be appreciatedthat optimization component 708 can include optimization code thatperforms utility based analysis in connection with assigning userdevices to beams and/or scheduling techniques. The optimization code canutilize artificial intelligence based methods in connection withperforming inference and/or probabilistic determinations and/orstatistical-based determinations in connection with optimizing userdevice beam assignments.

User device 700 can additionally comprise memory 710 that is operativelycoupled to processor 706 and that can store information related to beampattern information, CQI data, lookup tables comprising informationrelated thereto, and any other suitable information related tobeamforming and channel monitoring as described herein. Memory 710 canadditionally store protocols associated with generating lookup tables,etc., such that user device 700 can employ stored protocols and/oralgorithms to increase system capacity and performance. It will beappreciated that the data store (e.g., memories) components describedherein can be either volatile memory or nonvolatile memory, or caninclude both volatile and nonvolatile memory. By way of illustration,and not limitation, nonvolatile memory can include read only memory(ROM), programmable ROM (PROM), electrically programmable ROM (EPROM),electrically erasable ROM (EEPROM), or flash memory. Volatile memory caninclude random access memory (RAM), which acts as external cache memory.By way of illustration and not limitation, RAM is available in manyforms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronousDRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM(ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). Thememory 710 of the subject systems and methods is intended to comprise,without being limited to, these and any other suitable types of memory.The processor 706 is connected to a symbol modulator 712 and transmitter714 that transmits the modulated signal.

FIG. 8 is an illustration of a system 800 that facilitates increasingsystem capacity or performance in a communication environment inaccordance with various embodiments. System 800 comprises a base station802 with a receiver 810 that receives signal(s) from one or more userdevices 804 through one or more receive antennas 806, and transmits tothe one or more user devices 804 through a plurality of transmitantennas 808. In one or more embodiments, receive antennas 806 andtransmit antennas 808 can be implemented using a single set of antennas.Receiver 810 can receive information from receive antennas 806 and isoperatively associated with a demodulator 812 that demodulates receivedinformation. Receiver 810 can be, for example, a Rake receiver (e.g., atechnique that individually processes multi-path signal components usinga plurality of baseband correlators, . . . ), an MMSE-based receiver, orsome other suitable receiver for separating out user devices assignedthereto, as will be appreciated by one skilled in the art. According tovarious aspects, multiple receivers can be employed (e.g., one perreceive antenna), and such receivers can communicate with each other toprovide improved estimates of user data. Demodulated symbols areanalyzed by a processor 814 that is similar to the processor describedabove with regard to FIG. 7, and is coupled to a memory 816 that storesinformation related to user device assignments, lookup tables relatedthereto and the like. Receiver output for each antenna can be jointlyprocessed by receiver 810 and/or processor 814. A modulator 818 canmultiplex the signal for transmission by a transmitter 820 throughtransmit antennas 808 to user devices 804.

Base station 802 further comprises an assignment component 822, whichcan be a processor distinct from or integral to processor 814, and whichcan evaluate a pool of all user devices in a sector served by basestation 804 and can assign user devices to beams and/or schedulingtechniques based at least in part upon the CQIs for the channel of theindividual user devices.

FIG. 9 shows an exemplary wireless communication system 900. Thewireless communication system 900 depicts one base station and one userdevice for sake of brevity. However, it is to be appreciated that thesystem can include more than one base station and/or more than one userdevice, wherein additional base stations and/or user devices can besubstantially similar or different from the exemplary base station anduser device described below. In addition, it is to be appreciated thatthe base station and/or the user device can employ the systems (FIGS.7-9) and/or methods (FIGS. 4-6) described herein to facilitate wirelesscommunication there between.

Referring now to FIG. 9, on a downlink, at access point 905, a transmit(TX) data processor 910 receives, formats, codes, interleaves, andmodulates (or symbol maps) traffic data and provides modulation symbols(“data symbols”). A symbol modulator 915 receives and processes the datasymbols and pilot symbols and provides a stream of symbols. Symbolmodulator 915 multiplexes data and pilot symbols and provides them to atransmitter unit (TMTR) 920. Each transmit symbol may be a data symbol,a pilot symbol, or a signal value of zero. The pilot symbols may be sentcontinuously in each symbol period. The pilot symbols can be frequencydivision multiplexed (FDM), orthogonal frequency division multiplexed(OFDM), time division multiplexed (TDM), frequency division multiplexed(FDM), or code division multiplexed (CDM).

TMTR 920 receives and converts the stream of symbols into one or moreanalog signals and further conditions (e.g., amplifies, filters, andfrequency upconverts) the analog signals to generate a downlink signalsuitable for transmission over the wireless channel. The downlink signalis then transmitted through an antenna 925 to the user devices. At userdevice 930, an antenna 935 receives the downlink signal and provides areceived signal to a receiver unit (RCVR) 940. Receiver unit 940conditions (e.g., filters, amplifies, and frequency downconverts) thereceived signal and digitizes the conditioned signal to obtain samples.A symbol demodulator 945 demodulates and provides received pilot symbolsto a processor 950 for channel estimation and CQI calculations. Symboldemodulator 945 further receives a frequency response estimate for thedownlink from processor 950, performs data demodulation on the receiveddata symbols to obtain data symbol estimates (which are estimates of thetransmitted data symbols), and provides the data symbol estimates to anRX data processor 955, which demodulates (i.e., symbol demaps),deinterleaves, and decodes the data symbol estimates to recover thetransmitted traffic data. The processing by symbol demodulator 945 andRX data processor 955 is complementary to the processing by symbolmodulator 915 and TX data processor 910, respectively, at access point905.

On the uplink, a TX data processor 960 processes traffic data andprovides data symbols. The data symbols can include CQI data based uponthe received pilot. A symbol modulator 965 receives and multiplexes thedata symbols with pilot symbols, performs modulation, and provides astream of symbols. A transmitter unit 970 then receives and processesthe stream of symbols to generate an uplink signal, which is transmittedby the antenna 935 to the access point 905.

At access point 905, the uplink signal from user device 930 is receivedby the antenna 925 and processed by a receiver unit 975 to obtainsamples. A symbol demodulator 980 then processes the samples andprovides received pilot symbols and data symbol estimates for theuplink. An RX data processor 985 processes the data symbol estimates torecover the traffic data transmitted by user device 930. A processor 990performs channel estimation for each active user device transmitting onthe uplink. Multiple user devices may transmit pilot concurrently on theuplink on their respective assigned sets of pilot subbands, where thepilot subband sets may be interlaced.

Processors 990 and 950 direct (e.g., control, coordinate, manage, etc.)operation at access point 905 and user device 930, respectively.Respective processors 990 and 950 can be associated with memory units(not shown) that store program codes and data. Processors 990 and 950can utilize any of the methodologies described herein, including thoseillustrated in FIGS. 4-6 to select a scheduling technique or beamassignment for the user device 930. Respective Processors 990 and 950can also perform computations to derive frequency and impulse responseestimates for the uplink and downlink, respectively.

For a multiple-access system (e.g., FDMA, OFDMA, CDMA, TDMA, SDMA,etc.), multiple user devices can transmit concurrently on the uplink.For such a system, the pilot subbands may be shared among different userdevices. The channel estimation techniques may be used in cases wherethe pilot subbands for each user device span the entire operating band(possibly except for the band edges). Such a pilot subband structurewould be desirable to obtain frequency diversity for each user device.The techniques described herein may be implemented by various means. Forexample, these techniques may be implemented in hardware, software, or acombination thereof. For a hardware implementation, the processing unitsused for channel estimation may be implemented within one or moreapplication specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, micro-controllers, microprocessors,other electronic units designed to perform the functions describedherein, or a combination thereof. With software, implementation can bethrough modules (e.g., procedures, functions, and so on) that performthe functions described herein. The software codes may be stored inmemory unit and executed by the processors 990 and 950.

For a software implementation, the techniques described herein may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The software codes may be storedin memory units and executed by processors. The memory unit may beimplemented within the processor or external to the processor, in whichcase it can be communicatively coupled to the processor by various meansas is known in the art.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the aforementioned embodiments, but one of ordinary skill inthe art may recognize that many further combinations and permutations ofvarious embodiments are possible. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the appended claims.Furthermore, to the extent that the term “includes” is used in eitherthe detailed description or the claims, such term is intended to beinclusive in a manner similar to the term “comprising” as “comprising”is interpreted when employed as a transitional word in a claim.

1. A method for enhancing performance for a wireless communicationenvironment, comprising: generating a first pilot; transmitting thefirst pilot; and receiving at least one channel quality indicator (CQI)based at least in part upon the first pilot.
 2. A method of claim 1,further comprising scheduling at least one user device based at least inpart upon the at least one CQI.
 3. The method of claim 2, furthercomprising using at least one of spatial division multiplexing (SDM),multiple input multiple output (MIMO) and opportunistic beamformingscheduling techniques to schedule the at least one user device.
 4. Themethod of claim 1, further comprising assigning a user device to a beambased upon the at least one CQI.
 5. The method of claim 1, furthercomprising using a signal to interference to noise ratio (SINR) as theCQI.
 6. The method of claim 1, further comprising using a supportablerate over the channel as the CQI.
 7. The method of claim 1, the firstpilot is transmitted on a first beam and further comprising: generatinga second pilot; transmitting the second pilot on a second beam; andreceiving a second CQI based at least in part upon the second pilot. 8.The method of claim 1, the first pilot is transmitted over an areaincluding a plurality of beams.
 9. The method of claim 8, the at leastone CQI is based at least in part upon a set of beam weights.
 10. Themethod of claim 9, further comprising utilizing the set of beam weights.11. The method of claim 1, the at least one CQI is received every frame.12. The method of claim 1, the at least one CQI is received based uponat least one of spatial division multiplexing (SDM), multiple inputmultiple output (MIMO) and opportunistic beamforming scheduling.
 13. Themethod of claim 1, further comprising receiving a control channel CQI.14. The method of claim 13, the first pilot is transmitted on anantenna.
 15. The method of claim 1, further comprising modifying a beambased at least in part upon the at least one CQI.
 16. A method forenhancing performance for a wireless communication environmentcomprising: receiving a pilot; determining a CQI based at least in partupon the pilot; and transmitting the CQI to a base station.
 17. Themethod of claim 16, further comprising estimating a channel based on thepilot and a set of beam weights, the channel estimate is used indetermining the CQI.
 18. A wireless communication apparatus comprising:a processor configured to generate a first pilot, transmit the firstpilot and receive at least one CQI based at least in part upon the firstpilot; and a memory coupled with the processor.
 19. The wirelessapparatus of claim 18, the processor schedules at least one user devicebased at least in part upon the at least one CQI.
 20. The wirelessapparatus of claim 19, the processor uses at least one of spatialdivision multiplexing (SDM), multiple input multiple output (MIMO) andopportunistic beamforming scheduling techniques to schedule the at leastone user device.
 21. The wireless apparatus of claim 18, the processorassigns a user device to a beam based upon the at least one CQI.
 22. Thewireless apparatus of claim 18, the CQI is at least one of a signal tointerference to noise ratio (SINR) and a supportable over the channel.23. The wireless apparatus of claim 18, the processor is configured togenerate a second pilot, transmit the second pilot and receive a secondCQI based at least in part upon the second pilot.
 24. The wirelessapparatus of claim 18, the processor transmits the first pilot over anarea including a plurality of beams.
 25. The wireless apparatus of claim24, the at least one CQI is based at least in part upon a set of beamweights stored in the memory.
 26. The wireless apparatus of claim 25,the processor utilizes the set of beam weights.
 27. The wirelessapparatus of claim 18, the processor receives the at least one CQI everyframe.
 28. The wireless apparatus of claim 18, the processor receivesthe at least one CQI based upon at least one of spatial divisionmultiplexing (SDM), multiple input multiple output (MIMO) andopportunistic beamforming scheduling.
 29. The wireless apparatus ofclaim 18, the processor receives a control channel CQI.
 30. The wirelessapparatus of claim 29, the processor transmits the first pilot throughan antenna.
 31. A wireless communication apparatus comprising: aprocessor configured to receive a pilot, to determine at least one CQIbased at least in part upon the pilot and to transmit the CQI to a basestation; and a memory coupled with the processor.
 32. The wirelesscommunication apparatus of claim 31, the processor estimates a channelbased on the pilot and a set of beam weights, the channel estimate isused in determining the CQI.
 33. A wireless communication apparatus forenhancing performance for a wireless communication environment,comprising: means for generating a first pilot; means for transmittingthe first pilot; and means for receiving at least one channel qualityindicator (CQI) based at least in part upon the first pilot.
 34. Theapparatus of claim 33, further comprising means for scheduling at leastone user device based at least in part upon the at least one CQI. 35.The apparatus of claim 33, further comprising: means for generating asecond pilot; means for transmitting the second pilot on a second beam;and means for receiving a second CQI based at least in part upon thesecond pilot.
 36. The apparatus of claim 33, further comprising meansfor receiving a control channel CQI.
 37. The apparatus of claim 33,further comprising means for utilizing a set of beam weights, the atleast one CQI is based at least in part upon the set of beam weights.38. The apparatus of claim 33, further comprising means for modifying abeam based at least in part upon the at least one CQI.
 39. A wirelesscommunication apparatus for enhancing performance for a wirelesscommunication environment, comprising: means for receiving a pilot; andmeans for determining a CQI based at least in part upon the pilot; andmeans for transmitting the CQI to a base station.
 40. The apparatus ofclaim 39, further comprising means for estimating a channel based on thepilot and a set of beam weights, the channel estimate is used indetermining the CQI.
 41. A computer-readable medium having storedthereon computer-executable instructions for: generating a first pilot;transmitting the first pilot; and receiving at least one channel qualityindicator (CQI) based at least in part upon the first pilot.
 42. Thecomputer-readable medium of claim 41, further comprising instructionsfor scheduling at least one user device based at least in part upon theat least one CQI.
 43. The computer-readable medium of claim 41, furthercomprising instructions for assigning a user device to a beam based uponthe at least one CQI.
 44. The computer-readable medium of claim 41,further comprising instructions for: generating a second pilot;transmitting the second pilot on a second beam; and receiving a secondCQI based at least in part upon the second pilot.
 45. Acomputer-readable medium having stored thereon computer-executableinstructions for: receiving a pilot; and determining a CQI based atleast in part upon the pilot; and transmitting the CQI to a basestation.
 46. A processor that executes instructions for enhancingperformance for a wireless communication environment, the instructionscomprising: generating a first pilot; transmitting the first pilot; andreceiving at least one channel quality indicator (CQI) based at least inpart upon the first pilot.
 47. The processor of claim 46, furthercomprising scheduling at least one user device based at least in partupon the at least one CQI.
 48. The processor of claim 46, furthercomprising: generating a second pilot; transmitting the second pilot ona second beam; and receiving a second CQI based at least in part uponthe second pilot.
 49. A mobile device that facilitates communicatingover a wireless network, comprising: a component that generates a firstpilot; a component that transmits the first pilot; a component thatreceives a CQI based at least in part upon the first pilot; and acomponent that schedules at least one user device based at least in partupon the at least one CQI.
 50. The mobile device of claim 49, the deviceis at least one of a cellular phone, a smartphone, a handheldcommunication device, a handheld computing device, a satellite radio, aglobal positioning system, a laptop, and a PDA.
 51. A mobile device thatfacilitates communicating over a wireless network, comprising: acomponent that receives a pilot; a component that determines a CQI basedat least in part upon the pilot; and a component that transmits the CQIto a base station.
 52. The mobile device of claim 51, the device is atleast one of a cellular phone, a smartphone, a handheld communicationdevice, a handheld computing device, a satellite radio, a globalpositioning system, a laptop, and a PDA.